Question

Would you expect the first ionization enthalpies for two isotopes of the same element to be the same or different? Justify your answer.

Answer 1

Hint: Ionization enthalpy of any atom depends upon its nuclear charge means the number of protons and electrons present in the atom. Isotopes of any element will have the same no. of protons and electrons in it and thus the atomic number of the elements and its isotopes will be the same.

Complete step by step answer:
Ionization enthalpy or energy is defined as the minimum amount of energy required by an isolated atom to remove an outermost electron from the valence shell in its gaseous state or neutral state. And it mainly depends on the nuclear charge.
Isotopes are defined as the variants of a chemical element which have the same atomic number but the atomic mass and the physical properties of isotopes will be different from its chemical element. The chemical behavior of isotopes is similar. Isotopes only differ in the no. of neutrons in an atom, no. of protons and electrons will remain the same.
As we know that ionization enthalpy depends on the nuclear charge means the no. of protons and electrons. Isotopes of the same element will have the same number of electrons and protons in it which means that the atomic no. of the isotopes will be similar to the element but the number of neutrons will be different in the isotopes of the element.

Hence the ionization energy required to remove an electron from both the elements and its isotope will be the same because ionization energy does not depend on neutrons; it depends on the number of protons and electrons.
Thus the ionization enthalpies for two isotopes of the same element should be the same.

Note: The carbon atoms have three isotopes in nature that are carbon-12, carbon-13 and carbon 14. In these carbon isotopes the no. of protons or the electron is 6 but the number of neutrons in each of them is different that is 6,7, and 8. Thus the atomic number of all the isotopes will be six but the atomic mass will change. Among them carbon-14 is the heaviest.